Fairfax Accessory Dwelling Units – ADUs

   An accessory dwelling unit shall meet the following standards listed below.

   (A)   Owner occupancy. Either the primary residence or the accessory dwelling unit shall be owner-occupied.

   (B)   Rental. The unit shall not be sold separately from the primary residence and shall only be rented for terms of 30 days or more.

   (C)   Development on lot. A single-family dwelling or duplex must exist on the lot or will be constructed in conjunction with the accessory dwelling unit and be located within the RD 5.5-7, RS-6, RS 7.5, SF-RMP, UR or RM zoning districts. Accessory dwelling units are not allowed in conjunction with multiple residential development.

   (D)   Maximum number. A maximum of one accessory dwelling unit or junior accessory dwelling unit is allowed per lot.

   (E)   Unit. The accessory dwelling unit is either attached to the existing dwelling or located within the living area of the existing dwelling or detached from the existing dwelling and located on the same lot as the existing dwelling.

   (F)   Maximum size.

      (1)   The increased floor area of an attached accessory dwelling unit shall not exceed 50 percent of the existing living area, with a maximum increase in floor area of 1,200 square feet.

      (2)   The total area of floorspace for a detached accessory dwelling unit shall not exceed 1,200 square feet.

   (G)   Minimum size. The accessory dwelling unit shall contain no less than the 150 square feet area minimum required for an efficiency dwelling unit as defined in Section 17958.1 of the Health & Safety Code.

   (H)   Facilities. An accessory dwelling unit shall include permanent provisions for living, sleeping, eating, cooking, and sanitation. No passageway shall be required in conjunction with the construction of an accessory dwelling unit. PASSAGEWAY means a pathway that is unobstructed clear to the sky and extends from a street to one entrance of the accessory dwelling unit.

   (I)   Setback. No setback shall be required for a legally created existing garage that is converted to an accessory dwelling unit, and a setback of no more than five feet from the side and rear lot lines shall be required for an accessory dwelling unit that is constructed above a legally created garage. All other accessory dwelling units shall comply with the front, rear and side yard setback requirements of the underlying zoning district.

   (J)   Building and fire code compliance. The accessory dwelling unit shall comply with the Fairfax building and fire code requirements that apply to detached dwellings, as appropriate, including any requirements to obtain a building permit. See Town Municipal Code, Chapter 8.04 and Chapter 15.04. An accessory dwelling unit is not required to have fire sprinklers, if the primary residence is not required to have fire sprinklers.

   (K)   Sanitary service requirements. If an existing private septic system is to be utilized, the applicant must provide written confirmation from the Marin County Environmental Health Department that the existing sanitary system is adequate to handle the dwelling units it will serve.

   (L)   Parking.

      (1)   Except as provided in subparagraph (2):

         (a)   Accessory dwelling units must meet the following parking standards:

            1.   For accessory dwelling units with no separate bedrooms, one off-street parking space shall be provided for the accessory dwelling unit.

            2.   For accessory dwelling units with at least one separate bedroom, one off-street parking space shall be provided per bedroom.

         (b)   If parking is required:

            1.   The required parking spaces may be located on setback areas approved by the Director or tandem parking on an existing driveway, unless specific findings are made under subparagraph (2).

            2.   Parking arrangements in subparagraph (1) may be prohibited if the Director makes specific findings that such parking arrangements are not feasible based upon specific site or regional topographical or fire or life safety conditions, or that such arrangements are not permitted anywhere in the jurisdiction.

            3.   When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit, the replacement parking spaces may be located in any configuration on the same lot as the accessory dwelling unit, including, but not limited to, as covered spaces, uncovered spaces, tandem spaces, or by the use of mechanical automobile parking lifts.

      (2)   Parking standards shall not be imposed on an accessory dwelling unit if any of the following circumstances exist on the property:

         (a)   The accessory dwelling unit is located within one-half mile of public transit. For purposes of this section, “public transit” shall mean a public transit stop or station.

         (b)   The accessory dwelling unit is located within an architecturally and historically significant historic district.

         (c)   The accessory dwelling unit is part of the existing primary residence or an existing accessory structure.

         (d)   When on-street parking permits are required but not offered to the occupant of the accessory dwelling unit.

         (e)   When there is a car share vehicle located within one block of the accessory dwelling unit.

   (M)   Physical development standards. Except as otherwise provided in this chapter, the accessory dwelling unit shall meet all physical property development standards of the zoning district in which it is located, including but not limited to, height, lot size, floor area ratio and lot coverage.

   (N)   Architectural design standards. Any modifications to the exterior of the building, or construction of new structures, shall be strictly in keeping with the architectural character of the principal residence. The design of the accessory dwelling unit shall relate to the design of the primary residence by use of the similar exterior wall materials, colors, window types, door and window trims, roofing materials and roof pitch.

   (O)   Utilities. Utility service for sewer, water, electricity and gas (if necessary) shall be provided to the accessory dwelling unit.